Process for rendering porous electrodes impermeable to liquids



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EROCM S FOR EENDJERING IPQRQUS ELECTRODES IMPER'MEAIBLE 'ro LIQUIDS.

o Drawing.

To all whom it may concern:

Be it known that l, Runs UPPENHEIM, of

i2 and 33 Rue de Lorraine, Levallois-Perret,

Eaeine, France, engineer, have invented Processes for Rendering Porous Electrodes impermeable to. Liquids, of which the following is a full, clear, and exact description.

The present invention has for its object a process for rendering impermeable to a metallic oleo-margarate (the else-man garate of zinc, for example) which has the propert of forming upon the porous body a colloida pectized film, which is nondecomposable b an electric current, is a good condoctor 0 electricity and is impermeable to li uids but permeable to gases.

e term metallic soap as used herein, is intended to cover compounds of metals with the fatty acids, which are insoluble in water but generally more or less soluble in oily materials,

This metallic soap may, prepared as follows:

In a litre of water, preferably boilin there is dissolved 100 grammes of big i grade white-soap (such as Marseille soap), then this solution is mixed when cold with a solution of chloride of zinc titrating about 40 Baum. There is thus obtained a precipitate oif ole-margarate of zinc or soap or Z1110.

This precipitate, obtained after filtration, is spread by means of a spatula, for examp e, upon the orousbody, and thus forms upon it a col oidal pectized film, constituting a protective facing, which has the following properties :it is insoluble in water, impermeable to li uids, permeable to gases, non-decomposable y electric current, and a good conductor of electricitg.

This facing, which is chiefly a opted to be applied to the porous depolarizing carior example, be

good electric conduc Application filed October 1 9, 1923. Serial No. 669,625.

bon of the positive electrode of certain types of batteries, protects this porous carbon against access of water from the electrolyte, and at the same time preserves for the battery a low internal resistance, on account of the excessively small thickness of the colloidal pectized film and of its electric conductivity.

The pectized colloid of metallic oleo-margarate may also be formed by the immersion of the porous body the following conditions:

'llhe porous body is at first immersed in the solution of white soap, preferably boiling. The immersion should be carried out rapidly in such away that the liquid has no time to deeply penetrate into the mass. After immersion, the porous body is allowed to dry for several seconds, and is then immersed in the solution of the metallic salt, which may, for example, be chloride of zinc By the re-action of the chloride of zinc on the soap, oleo-margarate ofzinc, or soap of zinc is formed within the ores of the peripheral part of the porous ody, which is thereby protected against outside shocks, and slight scratches. Thus perfect impermeabilit is obtained 0 posing any penetraiii) tion of t e liquid into t e mass of the porous body.

Claims:

1. A process for renderin porous electrodes im ermeable to liqui s, which comprises app yin a metallicsoap to the porous electrode, so t at said soap forms on this porous body a colloidal pectized film, which is non-decomposable b" electric current, is a good-conductor of e ectricity, and is impermeable to liquids but permeable to gases.

2. A process for rendering porous electrodes impermeable to liquids, which com prises applying to the porous electrode a metallic oleo-margarate, so that thelatter forms on this orous body a colloidal pee tized film, which is non-decomposable by electric current, is agood conductor of electricity, and is impermeable to liquids but permeable to gases.

3. A process for rendering porous electrodes impermeable to liquids, which comprises applying to. the porous electrode on oleo-margarate of zinc, so that the latter forms on this orous body a colloidal pectized him, which is non-decomposable by electric current, is a good conductor of electricity, and is impermeable to liquids but permeable to gases.

4. A process for rendering porous electrodes impermeable to liquids, which oomprises dipping the porous body in a solution of white soap for a .very short time, in allowin the porous body to dry for several secon after this dipping, and in then dipping the body in a solution of a metallic sa t.

5. A process for rendering porous electrodes impermeable to liquids, which comprises dipping the porous bod in a solution of white soap for a very s ort time, in allowingthe porous body to dry for several seconds after this dipping, and in then dip: pin the bodyin asolution of zinc chloride.

'1 e foregoing specification of my process for rendering porous electrodes impermeable to liquids, signed by me this 5th day of October, 1923;

RENE OPPENHEIM. 

